Why all the "big" turbo kits @ low boost

[diss7]

Originally Posted by Ironsquid

Drivability on the low end has NOTHING to do with the size of the turbo and you are severely mistaken.

Wat.

Originally Posted by jamesm

you've very, very obviously never actually tuned or even driven in one of these cars equipped with the turbos you speak of.

you simply cannot make the same amount of horsepower on a 'properly sized' 28xx turbo that you can with a 30r or 35r on pump gas reliably. i know this, from experience. and yes, this engine is remarkable in the way it is able to spool these 'huge' turbos. there is almost no perceptible difference in 'lag' between my 2867r and a 3076r. the 3582r doesn't add much on top of that.

and xx psi @ xxxx rpm does not effectively quantify how responsive a turbo feels. the t3/t4 hybrids build more boost at lower rpm than the gtx's (maybe, depends which ones you're comparing), yet feel far less responsive.

speak from experience. if you were, you wouldn't be saying the things that you are.

James, don't think you are suddenly knowledgable about everything, because you have starting tuning cars; and that everyone else is inexperienced.
All the cars and turbos I have quoted, I owned, and tracked them. Granted I didn't tune them.

If there is no lag difference between your gtx2867r and a gtx3076r, I blame the tune, or the car. Show me a dyno where one turbo has been taken off and replaced with the other and there is no lag difference. You can see on the PTUNING kit where the max boost is reached. Its around 500 - 1000rpm later than a gtx28, depending on whos dyno you are comparing it to.

I'm not saying that a gtx28 turbo will make the same power as a gtx30. I'm saying that using a gtx30/35 for a hp target that a gtx28 can easily reach is not always better.

I spent the day at the track yesterday driving my ae86 drift car. 2000cc, 400whp. Spins up 4th gear while spooling. It just makes me laugh when I'm out there driving that, that there are people here talking about having more than that in a street car.
This is pump gas. 10:1 static comp.

Oh, and its a t28 frame turbo. (Tomei M8270) Not even BB.




Granted, I am considering replacing that turbo with a gtx3067r. I think it's well suited to what I want from the motor. I'll stick around the 400whp mark, but it should spool sooner (because BB and billet), and run cooler. But, take note, I'm at the 400whp mark, making the call to go from t28 frame to t30 frame. I wouldn't be making that call at 300whp. gtx28 for 300whp all day erry day.

Look, we all have different goals, and I'm doing is putting forward a counter arguement; as I dont like seeing a heavily one sided thread, which will then lead others to believe its fact.

[Ironsquid]

Originally Posted by diss7

Wat.



James, don't think you are suddenly knowledgable about everything, because you have starting tuning cars; and that everyone else is inexperienced.
All the cars and turbos I have quoted, I owned, and tracked them. Granted I didn't tune them.

If there is no lag difference between your gtx2867r and a gtx3076r, I blame the tune, or the car. Show me a dyno where one turbo has been taken off and replaced with the other and there is no lag difference. You can see on the PTUNING kit where the max boost is reached. Its around 500 - 1000rpm later than a gtx28, depending on whos dyno you are comparing it to.

I'm not saying that a gtx28 turbo will make the same power as a gtx30. I'm saying that using a gtx30/35 for a hp target that a gtx28 is not always better.

I spent the day at the track yesterday driving my ae86 drift car. 2000cc, 400whp. Spins up 4th gear while spooling. It just makes me laugh when I'm out there driving that, that there are people here talking about having more than that in a street car.
This is pump gas. 10:1 static comp.

Oh, and its a t28 frame turbo. (Tomei M8270) Not even BB.



Look, we all have different goals, and I'm doing is putting forward a counter arguement; as I dont like seeing a heavily one sided thread, which will then lead others to believe its fact.

Do you even realize that a bigger turbo flows air more efficiently, even at low speeds? Sounds like you dont. 12 psi on a 28/30 is much different than 12 psi on a 35. Ever wonder why a car with a 28/30 pushing 12 psi gets beat by a car with a 35r at 10 psi? Its called VE.

[TRD_07]

So given how heat management is crucial on this car jumping to a turbo slightly bigger than what you initially had in mind would benefit you all around. I had in mind a gtx2867r because of its great success but now I'm tossing that option out and going a step further.

[diss7]

Originally Posted by Ironsquid

Well said personal preference. But alot of what im seeing in this thread are people claiming big turbos arent drivable, a waste, unbearably laggy, etc.

I urge people in this thread please do research, I mean actual research, not regurgitated forum posts. Dont claim things you dont know about and please for the love of god dont over exaggerate or mistake low end power for low end city driving response, they are two different things. Oh and dont apply what you know about low compression turbo motors to this one.

I'm quoting this, as its the smartest thing I've seen you say, and I agree with it.

All I will add, is that you can still compare it to other motors, but go in knowing the difference. When I was trying to to research on my 3sge beams, all I had to compare it to was a sr20. But I know my beams was a better motor, so it would perform better.

High comp helps spool and response of all turbos. It might make a big turbo streetable for you. But it will also make a smaller turbo, that much more responsive.

[diss7]

Originally Posted by TRD_07

So given how heat management is crucial on this car jumping to a turbo slightly bigger than what you initially had in mind would benefit you all around. I had in mind a gtx2867r because of its great success but now I'm tossing that option out and going a step further.

IMO, to realise the gains the gtx2867r has over a gtx2863r, you should really go to a t3 turbine, and go with the gtx3067r. There are certain turbos that I think are mismatched, and I would skip them.

The gtx turbos I would chose would be
gtx2860r 0.63
gtx2863r 0.86
gtx3067r 0.63
gtx3071r 0.63
gtx3576r 0.63
gtx3582r 0.86

Starting at the smallest, which would be my choice for 275whp. Each one would be my choice adding another 50whp.

They'll all do more than that, and obviously well less as well, but they'd be my choices.

[Ironsquid]

Originally Posted by diss7

I'm quoting this, as its the smartest thing I've seen you say, and I agree with it.

All I will add, is that you can still compare it to other motors, but go in knowing the difference. When I was trying to to research on my 3sge beams, all I had to compare it to was a sr20. But I know my beams was a better motor, so it would perform better.

High comp helps spool and response of all turbos. It might make a big turbo streetable for you. But it will also make a smaller turbo, that much more responsive.

I appreciate the acknowledgement. I still dont like that you are comparing responsiveness with turbo lag. If you had said, hey i do alot of short track autoX events and I need corner exit power, I would say awesome sounds like you know what you need/want.

[diss7]

Originally Posted by Ironsquid

Do you even realize that a bigger turbo flows air more efficiently, even at low speeds? Sounds like you dont. 12 psi on a 28/30 is much different than 12 psi on a 35. Ever wonder why a car with a 28/30 pushing 12 psi gets beat by a car with a 35r at 10 psi? Its called VE.

Don't assume that I don't know what I'm talking about, simply because I have a different opinion.

You do realise its power that bends rods. Not boost. The rods will bend from power.

Its like you think turbo a @ 10psi making 300whp, and turbo b at 8psi making 350whp, that the motor is under less strain with turbo b.

Edit - (obviously there are situations where turbo b will be less stresss, if for example turbo a is really poor VE)

The the point I'm trying to get across, is that I see signs on these forums that people thing turbo boost is the governing thing; and that a large frame kit like ptuning running 6psi and making 340?hp is just as safe as a small frame kit like avo running 6psi and making 240hp.

Anyway, I've put enough counter points forward to raise some discussion. I'm not here to convince anyone to my line of thinking; and I don't necessarily think you big frame boys were either. People need to make their own decisions.

James for example, he had one turbo, went for a ride in another car with a different turbo, and now wants to go that way. Thats the best scenario, when you can experience that, and make the call yourself. I've had similar experiences, but the other way; enjoying my car better with a smaller turbo.

[Ironsquid]

Originally Posted by diss7

Don't assume that I don't know what I'm talking about, simply because I have a different opinion.

You do realise its power that bends rods. Not boost. The rods will bend from power.

Its like you think turbo a @ 10psi making 300whp, and turbo b at 8psi making 350whp, that the motor is under less strain with turbo b.

Motors never been an issue for me, its the drivetrain parts that low end "snappy"
torque breaks. Progressive power v/s sudden power, thats the risk you assume.

[AVOturboworld]

Originally Posted by Ironsquid

Motors never been an issue for me, its the drivetrain parts that low end "snappy"
torque breaks. Progressive power v/s sudden power, thats the risk you assume.

How is the below "sudden" power in comparison to a large frame turbo that goes from nothing to 14psi within a short 1000rpm?



Yes, it's responsive. But sudden? Far less sudden than a setup that is basically doing nothing till 4000 then gains up to 200ft/lbs of torque over 800rpm. Now, that's sudden.

However, a large turbo is certainly easier to tune - you don't have to do much to the tuning until you are well into open loop.

[diss7]

Originally Posted by Ironsquid

Motors never been an issue for me, its the drivetrain parts that low end "snappy"
torque breaks. Progressive power v/s sudden power, thats the risk you assume.

Fair point.

But some people want sudden power. Like me.

Sudden turbo spool is awesome for drifting, for the exact reason you hate it. It breaks traction.

Upgraded axles are a cheap fix. The box is all down to how you drive it. I destroyed my synchros NA.

[Ironsquid]

Originally Posted by AVOturboworld

How is the below "sudden" power in comparison to a large frame turbo that goes from nothing to 14psi within a short 1000rpm?



Yes, it's responsive. But sudden? Far less sudden than a setup that is basically doing nothing till 4000 then gains up to 200ft/lbs of torque over 800rpm. Now, that's sudden.

However, a large turbo is certainly easier to tune - you don't have to do much to the tuning until you are well into open loop.

Shouldnt you be fixing your breather tank orders? I cant in good faith accept your advice when you arent shipping the correct parts.

And you threw up a dynograph without saying what turbo was used and I assume thats an 86.

This entire thread makes me really sad.

Just noticed you said large frame turbo. You realize they are putting bigger wheels in smaller housings now right? This isnt the 90s

[mrk1]

Originally Posted by diss7

Look, we all have different goals, and I'm doing is putting forward a counter arguement; as I dont like seeing a heavily one sided thread, which will then lead others to believe its fact.

A+, this thread just has big turbo in the title so its more of the people who choose larger turbos.

[diss7]

Originally Posted by vgi

at what psi you're getting 400whp? and would you run that pressure on stock brz/frs engine?

That graph is 0.9 bar and 1.1bar.

The dyno above is a motor with headwork (but still stock cams) bigger valves, and custom intake and exhaust manifolds.

Remember psi is a measure of the restriction of the motor, in other words the pressure is a result of a restriction. Having custom manifolds and head work allows the motor to breath easier, so it is less of a restriction, so it takes more air at the same psi. For example, that same turbo on an sr20 needs 1.5bar to get to the level I reached with 1.1bar. But the turbo is out of puff at that power, so I run the 0.9 bar (400whp) as my map.

As for the fa20, its more a case of knock than psi. I'm not in a position to comment on what is safe and what isn't. I'm not a tuner, and haven't boosted my car yet. But the more I see 400hp + builds, it gives me faith in raping the car at 300whp.

[Coheed]

Originally Posted by diss7

IMO, to realise the gains the gtx2867r has over a gtx2863r, you should really go to a t3 turbine, and go with the gtx3067r. There are certain turbos that I think are mismatched, and I would skip them.

The gtx turbos I would chose would be
gtx2860r 0.63
gtx2863r 0.86
gtx3067r 0.63
gtx3071r 0.63
gtx3576r 0.63
gtx3582r 0.86

Starting at the smallest, which would be my choice for 275whp. Each one would be my choice adding another 50whp.

They'll all do more than that, and obviously well less as well, but they'd be my choices.

The ns111 wheel has more power potential and no hit to response, transient or boost onset. It would be much better suited to use the .86 housing on the GTX turbos, because they flow more air than the standard versions. In all my testing (take with grain of salt) the .86 housing was better all around for the t2 flanged turbos utilizing the ns111 wheel. I'd actually take the ns111 over the T30 because it is more efficient. It can actually flow very similar to the T30 turbine in the .63 housing, perhaps a bit more. It's a great wheel with low inertia and great response. The only combo I don't much care for is the 71mm GT30r compressor being used with it. The turbine flows well but the torque moment isn't large enough to drive the compressor that size efficiently.

Mind you, all my testing has been done at higher elevations. This has an impact on the turbos performance in a lot of different ways, so sea level results can vary to my personal experiences. Likewise, I've tested a lot of the housings for several of the garrett turbos and the .86/.82 housings have always out-performed the smaller counterparts without any cons to how the power is delivered. The smaller housings do seem to spool a bit softer and give a more linear feel to how the boost is felt. The larger housings can have a rather abrupt boost onset which could be a bit harder to control, but I love the feeling!

I tested the .63/.82/1.06 housing on a GT3076r back to back and the larger housing did make more power. The 1.06 had iffy transient response, but really just felt like a non-bb turbo. The compressor never surged with this housing though, unlike the others. I bet the 1.06 would work decently well with the non-ported shroud compressor cover. Should help improve the efficiency of the compressor. I don't have the time or resources to do this kind of testing anymore.